Commit 55c97f3e authored by David S. Miller's avatar David S. Miller
Browse files

[TCP]: Fix __tcp_push_pending_frames() 'nonagle' handling. 



'nonagle' should be passed to the tcp_snd_test() function
as 'TCP_NAGLE_PUSH' if we are checking an SKB not at the
tail of the write_queue.  This is because Nagle does not
apply to such frames since we cannot possibly tack more
data onto them.

However, while doing this __tcp_push_pending_frames() makes
all of the packets in the write_queue use this modified
'nonagle' value.

Fix the bug and simplify this function by just calling
tcp_write_xmit() directly if sk_send_head is non-NULL.

As a result, we can now make tcp_data_snd_check() just call
tcp_push_pending_frames() instead of the specialized
__tcp_data_snd_check().

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2e2a59c

include/net/tcp.h

+0 −1
Original line number Diff line number Diff line
@@ -848,7 +848,6 @@ extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 


/* tcp_output.c */



extern void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb);

extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,

				      unsigned int cur_mss, int nonagle);

extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp);

net/ipv4/tcp_input.c

+7 −10
Original line number Diff line number Diff line
@@ -3346,12 +3346,9 @@ static inline void tcp_check_space(struct sock *sk) 
	}

}



static __inline__ void tcp_data_snd_check(struct sock *sk)

static __inline__ void tcp_data_snd_check(struct sock *sk, struct tcp_sock *tp)

{

	struct sk_buff *skb = sk->sk_send_head;



	if (skb != NULL)

		__tcp_data_snd_check(sk, skb);

	tcp_push_pending_frames(sk, tp);

	tcp_check_space(sk);

}
@@ -3645,7 +3642,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, 
				 */

				tcp_ack(sk, skb, 0);

				__kfree_skb(skb); 

				tcp_data_snd_check(sk);

				tcp_data_snd_check(sk, tp);

				return 0;

			} else { /* Header too small */

				TCP_INC_STATS_BH(TCP_MIB_INERRS);
@@ -3711,7 +3708,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, 
			if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) {

				/* Well, only one small jumplet in fast path... */

				tcp_ack(sk, skb, FLAG_DATA);

				tcp_data_snd_check(sk);

				tcp_data_snd_check(sk, tp);

				if (!tcp_ack_scheduled(tp))

					goto no_ack;

			}
@@ -3789,7 +3786,7 @@ step5: 
	/* step 7: process the segment text */

	tcp_data_queue(sk, skb);



	tcp_data_snd_check(sk);

	tcp_data_snd_check(sk, tp);

	tcp_ack_snd_check(sk);

	return 0;
@@ -4099,7 +4096,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 
		/* Do step6 onward by hand. */

		tcp_urg(sk, skb, th);

		__kfree_skb(skb);

		tcp_data_snd_check(sk);

		tcp_data_snd_check(sk, tp);

		return 0;

	}
@@ -4290,7 +4287,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 


	/* tcp_data could move socket to TIME-WAIT */

	if (sk->sk_state != TCP_CLOSE) {

		tcp_data_snd_check(sk);

		tcp_data_snd_check(sk, tp);

		tcp_ack_snd_check(sk);

	}

net/ipv4/tcp_output.c

+1 −14
Original line number Diff line number Diff line
@@ -894,24 +894,11 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, 
	struct sk_buff *skb = sk->sk_send_head;



	if (skb) {

		if (!tcp_skb_is_last(sk, skb))

			nonagle = TCP_NAGLE_PUSH;

		if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||

		    tcp_write_xmit(sk, cur_mss, nonagle))

		if (tcp_write_xmit(sk, cur_mss, nonagle))

			tcp_check_probe_timer(sk, tp);

	}

}



void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_sock *tp = tcp_sk(sk);



	if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||

	    tcp_packets_in_flight(tp) >= tp->snd_cwnd ||

	    tcp_write_xmit(sk, tcp_current_mss(sk, 1), tp->nonagle))

		tcp_check_probe_timer(sk, tp);

}



/* This function returns the amount that we can raise the

 * usable window based on the following constraints

 *

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